creating a lib

Author: addisonbeck

docs/contributing/creating-a-lib.md

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+# Creating a New Library
+
+This guide explains how to create a new library in the Bitwarden monorepo using Nx.
+    
+## Prerequisites
+
+- Node.js and npm installed
+- Bitwarden monorepo cloned and dependencies installed
+- The Nx cli installed, or accessible over npx
+
+## Creating a Library with Nx
+
+We use the `@nx/js` plugin to generate new libraries. Follow these steps to create a new library:
+
+1. From the root of the monorepo, run the generator command:
+
+   nx g @nx/js:lib my-new-lib --directory=libs/my-new-lib
+
+   Replace `my-new-lib` with the name of your library.
+
+2. The generator will ask you questions about the library configuration. Here are recommended settings:
+
+   - **Which bundler would you like to use?** Select `none` (we use our own bundling setup)
+   - **What should be the project name?** The same name as your library (e.g., `my-new-lib`)
+   - **Would you like to add a package.json?** Select `Yes` 
+   - **Which unit test runner would you like to use?** Select `jest` (our standard test runner)
+
+3. Once generated, the library will have this structure:
+
+```
+libs/
+  my-new-lib/
+    src/
+      index.ts
+      my-new-lib.ts
+    tsconfig.json
+    project.json
+    package.json
+    jest.config.js
+```
+
+4. Update the `package.json` with the appropriate Bitwarden naming convention:
+
+```json
+{
+  "name": "@bitwarden/my-new-lib",
+  "version": "0.0.0"
+}
+```
+
+5. Update the library's path in the root `tsconfig.base.json` file to make it available to other projects:
+
+```json
+{
+  "compilerOptions": {
+    "paths": {
+      "@bitwarden/my-new-lib": ["libs/my-new-lib/src"],
+    }
+  }
+}
+```
+
+## Building and Testing the Library
+
+- Build the library: `nx build my-new-lib`
+- Test the library: `nx test my-new-lib`
+- Lint the library: `nx lint my-new-lib`
+
+## Importing Your Library in Other Projects
+
+Once your library is created and built, you can import it in other projects within the monorepo:
+
+```ts
+import { someFunction } from "@bitwarden/my-new-lib";
+```
+
+## Best Practices
+
+- Follow the Bitwarden code style guidelines
+- Document your library's public API
+- Write unit tests for your library's functionality
+- If your library has dependencies on other libraries, make sure to add them to the `project.json` file